Manometers measure pressure by comparing it to the gravitational force exerted on a column of liquid. There are several types of manometers: 1) A U-tube manometer is the simplest, using two legs of equal area connected by a tube filled with a liquid like mercury to measure gas or liquid pressure. 2) An enlarged manometer has one leg with a larger area than the other and a float to indicate the pressure reading. 3) A well manometer has one simple tube leg and one enlarged well leg, providing greater sensitivity with small liquid level displacements in the well.

1. Types of
Manometers

2. Introduction
• Pressure measurement is one of the most important measurement in
continuous process industries.
• Manometers measure the unknown pressure by balancing against the
gravitational force of liquid heads.

3. Manometer
• Manometer refers to the measurement of pressure by comparison to
the hydraulic pressure produced by a column of liquid.
• With the help of manometer, we can measure comparatively high
pressure and negative pressure also.

4. Types covered
• U tube manometer.
• Enlarged manometer.
• Well type manometer.
• Inclined tube manometer.

5. U tube manometer
• Simplest manometer.
• Used in the measurement of liquid or gas
pressure.
• Both legs have same area.
• Manometric fluid of known specific gravity
is used.
• Mercury is generally used as fluid.

6. Enlarged manometer
• In the enlarged-leg manometer, a2 is
not negligible compared to a1. It has
a float in the enlarged-leg which is
utilized for indication or recording.
The two legs can be changed for
changing the measurement span.

7. Well type manometer
• One leg is a simple tube, other leg is a
large well.
• For small displacement of liquid level in
the well there will be a large change in the
height of simple tube.

8. Inclined tube manometer
• It is slant manometer.
• The angle of measuring leg is about 10⁰.
• Inclination is done to improve the
sensitivity.
• This manometer is used to measure very
small pressure difference.

9. Bourdon Gauge
• Key concept: pressure difference
across different areas of inner and
outer surfaces causes crescent to
flex

10. Bellow pressure gauge
• Bellow pressure gauge used a
column of liquid such as water or the
liquid metal mercury suspended by a
vacuum.
• It use the sealed chamber as a
reference pressure and are driven by
the external pressure.